﻿#region Copyright & License

// Copyright © 2012 - 2013 François Chabot, Yves Dierick
// 
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// 
// http://www.apache.org/licenses/LICENSE-2.0
// 
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#endregion

using System;
using System.Diagnostics;
using System.Text.RegularExpressions;
using Be.Stateless.Extensions;

namespace Be.Stateless.BizTalk.Runtime.Caching
{
	public class RegexCache : Cache<string, Regex>
	{
		public static RegexCache Instance
		{
			get { return _instance; }
		}

		#region Base Class Member Overrides

		protected override string ConvertKeyToString(string key)
		{
			ValidateKey(key);
			return key;
		}

		protected override Regex CreateItem(string key)
		{
			ValidateKey(key);
			return new Regex(key, RegexOptions.Compiled);
		}

		#endregion

		#region Helpers

		[Conditional("DEBUG")]
		private static void ValidateKey(string key)
		{
			if (key.IsNullOrEmpty()) throw new ArgumentNullException("key");
		}

		#endregion

		private static readonly RegexCache _instance = new RegexCache();
	}
}
